Two-dimensional (2D) Ti3C2 was synthesized by the exfoliation of Ti3AlC2 with HF solution and subsequently intercalation with dimethyl sulfoxide. As anode for lithium ion batteries, Ti3C2 after ...intercalation had an obvious higher capacity than that before intercalation. The capacity can be 123.6mAhg−1 at 1C rate with a coulombic efficiency of 47%. It is higher than that of 2D Ti2C and close to the theoretical capacity of Ti3C2 with F termination. It was suggested that MXene with pure F groups may be a way to further improve its Li storage performance.
•2D Ti3C2 after intercalation has larger c and larger lamella thickness.•In-Ti3C2 has capacity close to theoretical capacity with F termination.•In-Ti3C2 has better electrochemical performance than Ex-Ti3C2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Ti3C2 from PLS-Ti3AlC2 was highly oriented compared to that from HP-Ti3AlC2.•Small balls of possible AlF3 attached on the edge of MXene sheets were observed.•MXene is thermally stable in Ar ...atmosphere up to 800°C.•A structure of nano-anatase on 2D Ti3C2 was formed by 200°C oxidization.
We investigated the synthesis of quasi-two-dimensional carbide (Ti3C2), with the name of MXene, by immersing Ti3AlC2 in 40% or 49% hydrofluoric acid (HF) at 0°C, 15°C or 60°C. The influences of time, temperature, and source of Ti3AlC2 on the synthesis were researched. It was found that Ti3C2 synthesized from pressureless synthesized Ti3AlC2 was highly oriented compared to that from hot-pressed Ti3AlC2. As-synthesized Ti3C2 could be further exfoliated by intercalation with urea, dimethylsulfoxide or ammonia. From the results of thermogravimetry and differential scanning calorimetry, Ti3C2 MXene with F/OH termination was found to be stable in argon atmosphere at temperature up to 800°C. In oxygen atmosphere, at 200°C, parts of MXene layers were oxidized to obtain an interesting structure: anatase nano-crystals were evenly distributed on 2D Ti3C2 layers. At 1000°C, MXene layers were completely oxidized and anatase phase fully transformed to rutile in oxygen atmosphere.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Long non-coding RNAs (lncRNAs) play critical functions in various cancers. Firre intergenic repeating RNA element (FIRRE), a lncRNA located in the nucleus, was overexpressed in colorectal cancer ...(CRC). However, the detailed mechanism of FIRRE in CRC remains elusive. Results of RNA sequence and qPCR illustrated overexpression of FIRRE in CRC cell lines and tissues. The aberrant expression of FIRRE was correlated with the migration, invasion, and proliferation in cell lines. In accordance, it was also associated with lymphatic metastasis and distant metastasis in patients with CRC. FIRRE was identified to physically interact with Polypyrimidine tract-binding protein (PTBP1) by RNA pull-down and RNA immunoprecipitation (RIP). Overexpression of FIRRE induced the translocation of PTBP1 from nucleus to cytoplasm, which was displayed by immunofluorescence and western blot. In turn, delocalization of FIRRE from nucleus to cytoplasm is observed after the loss of PTBP1. The RNA-protein complex in the cytoplasm directly bound to BECN1 mRNA, and the binding site was at the 3' end of the mRNA. Cells with FIRRE and PTBP1 depletion alone or in combination were treated by Actinomycin D (ACD). Results of qPCR showed FIRRE stabilized BECN1 mRNA in a PTBP1-medieated manner. In addition, FIRRE contributed to autophagy activity. These findings indicate FIRRE acts as an oncogenic factor in CRC, which induces tumor development through stabilizing BECN1 mRNA and facilitating autophagy in a PTBP1-mediated manner.
We present a high-resolution 3-D radial anisotropy shear wave crustal model of SE Tibet by jointly inverting Rayleigh and Love dispersion curves from ambient noise recorded by CHINArray Phase I ...network. Our crustal shear wave model displays similar velocity features as the previous studies. Our radial anisotropy model reveals new information of radial anisotropy in the crust, implying different deformation patterns operating in the crust. Widespread positive radial anisotropy (Vsh > Vsv) is imaged in the crust across most of our study areas, which could result from the sub-horizontal aligned crustal materials caused by the ductile deformation and expansion of the Tibetan Plateau. Negative radial anisotropy is observed in the crust of the northern and central segments of the Xiaojiang fault (XJF). However, only the upper crust in the southern segment is imaged as the negative radial anisotropy. We consider vertical alignments of the cracks, faults and the crustal minerals in the middle and upper crust are the origin of the negative radial anisotropy. This pattern is also associated with the activities of the XJF and further implies the deformation mechanism is different between the segments. Neutral radial anisotropy is observed in the inner zone of Emeishan Large Igneous Province, which can be attributed to the equilibrium of the horizontal sills and the vertical dikes of the magma system. Our model provides new insights into the deformation pattern of SE Tibet.
•We follow Ockham's razor principle to construct a new crustal radial anisotropy shear wave velocity model in SE Tibet.•Neutral radial anisotropy is observed in the inner zone of Emeishan Large Igneous Province.•Different radial anisotropy pattern is found along the Xiaojiang Fault and Lijiang-Xiaojinhe Fault.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, using continuous Calderón’s reproducing formulas, we obtain algebras of Calderón–Zygmund operators on spaces of homogenous type in the setting of both one parameter and bi-parameter. ...More precisely, all classical Calderón–Zygmund operators form an algebra when
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Previous studies have defined "workaholic" effort as "bad effort" while work engagement is defined as "good effort." Active overtime is a mapping of work effort, but at this stage there is still ...relatively little exploration of the motivation behind "good effort" in the Chinese context.
This study explores the reasons that promote employees' initiative to perform overtime work in Chinese enterprises based on the two-factor theory. The study mainly used data empirical research approaches, including exploratory factor analysis, validation factor analysis, and data modeling. The questionnaire scale was developed based on factors that have been proven to be of high reliability and validity. The data are mainly for employees who are currently employed in Chinese companies.
We received a total of 1741 valid questionnaires, which provided a good database for this study. The results of the study show that both motivational and hygiene factors can positively promote employees' motivation to intentionally work overtime to a certain extent. Among them, overtime culture, institutional agreement, good physical office environment, career growth, financial rewards, and work challenges can positively promote motivation to work overtime. Work stress can increase the frequency and intensity of overtime work, but negatively promote motivation to work overtime. The study helps to improve enterprise management, optimize work design, and enhance psychological satisfaction.
In the domain of optical fiber distributed acoustic sensing, the persistent challenge of extending sensing distances while concurrently improving spatial resolution and frequency response range has ...been a complex endeavor. The amalgamation of pulse compression and frequency division multiplexing methodologies has provided certain advantages. Nevertheless, this approach is accompanied by the drawback of significant bandwidth utilization and amplified hardware investments. This study introduces an innovative distributed optical fiber acoustic sensing system aimed at optimizing the efficient utilization of spectral resources by combining compressed pulses and frequency division multiplexing. The system continuously injects non-linear frequency modulation detection pulses spanning various frequency ranges. The incorporation of non-uniform frequency division multiplexing augments the vibration frequency response spectrum. Additionally, nonlinear frequency modulation adeptly reduces crosstalk and enhances sidelobe suppression, all while maintaining a favorable signal-to-noise ratio. Consequently, this methodology substantially advances the spatial resolution of the sensing system. Experimental validation encompassed the multiplexing of eight frequencies within a 120 MHz bandwidth. The results illustrate a spatial resolution of approximately 5 m and an expanded frequency response range extending from 1 to 20 kHz across a 16.3 km optical fiber. This achievement not only enhances spectral resource utilization but also reduces hardware costs, making the system even more suitable for practical engineering applications.
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MXenes are novel graphene-like 2-D materials. Cu2O is an effective additive for thermal decomposition of ammonium perchlorate (AP). We reported the synthesis of MXene (Ti3C2), Cu2O and MXene-Cu2O ...respectively. The samples were characterized by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Results indicate that the MXene is composed of lots of nano-sheets and the thickness is 30 ± 10 nm, and Cu2O nanoparticles nucleate and grow heterogeneously directly on the surface of MXene. The effect of these MXene, Cu2O and MXene-Cu2O samples on the thermal decomposition of AP were investigated using TG-DSC. The results revealed that MXene-Cu2O have a great influence on the thermal decomposition of AP than that of pure MXene and Cu2O.
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•MXene-Cu2O nanocomposite has been synthesized firstly.•Cu2O heterogeneous nucleate and grow on the surface of MXene directly.•The thermal decomposition of AP was studied with different samples.•MXene-Cu2O has a great influence on the thermal decomposition of AP than that of pure MXene and Cu2O.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To determine if limb lengths, as markers of early life environment, are associated with the risk of diabetes in China.
We performed a cohort analysis using data from the China Health and Retirement ...Longitudinal Study (CHARLS), and multivariable-adjusted Cox proportional hazard regression models were used to examine the associations between baseline limb lengths and subsequent risk of diabetes.
The CHARLS, 2011-2018.
The study confined the eligible subject to 10 711 adults aged over 45 years from the CHARLS.
During a mean follow-up period of 6·13 years, 1358 cases of incident diabetes were detected. When controlling for potential covariates, upper arm length was inversely related to diabetes (hazard ratio (HR) 0·95, 95 % CI (0·91, 0·99),
= 0·028), and for every 1-cm difference in knee height, the risk of diabetes decreased by about 4 % (HR 0·96, 95 % CI (0·93, 0·99),
= 0·023). The association between upper arm length and diabetes was only significant among females while the association between knee height and diabetes was only significant among males. In analyses stratified by BMI, significant associations between upper arm length/knee height and diabetes only existed among those who were underweight (HR 0·91, 95 % CI (0·83, 1·00),
= 0·049, HR 0·92, 95 % CI (0·86, 0·99),
= 0·031).
Inverse associations were observed between upper arm length, knee height and the risk for diabetes development in a large Asian population, suggesting early life environment, especially infant nutritional status, may play an important role in the determination of future diabetes risk.
The large amount of sampled data in coherent phase-sensitive optical time-domain reflectometry (Φ-OTDR) brings heavy data transmission, processing, and storage burdens. By using the comparator ...combined with undersampling, we achieve simultaneous reduction of sampling rate and sampling resolution in hardware, thus greatly decreasing the sampled data volume. But this way will inevitably cause the deterioration of detection signal-to-noise ratio (SNR) due to the quantization noise’s dramatic increase. To address this problem, denoising the demodulated phase signals using compressed sensing, which exploits the sparsity of spectrally sparse vibration, is proposed, thereby effectively enhancing the detection SNR. In experiments, the comparator with a sampling parameter of 62.5 MS/s and 1 bit successfully captures the 80 MHz beat signal, where the sampled data volume per second is only 7.45 MB. Then, when the piezoelectric transducer’s driving voltage is 1 Vpp, 300 mVpp, and 100 mVpp respectively, the SNRs of the reconstructed 200 Hz sinusoidal signals are respectively enhanced by 23.7 dB, 26.1 dB, and 28.7 dB by using compressed sensing. Moreover, multi-frequency vibrations can also be accurately reconstructed with a high SNR. Therefore, the proposed technique can effectively enhance the system’s performance while greatly reducing its hardware burden.
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